1937 Desoto engine needed, will a 1951 Desoto work?

[rustystuff]

Greetings! I recently bought a 1937 Desoto rumble seat coupe, looks mostly complete but the engine is seized and in pieces so I would like to find a bolt in replacement engine for now. I found a 1951 Desoto engine with a S15 stamp on the block. Would this engine be a bolt in replacement for my 1937 engine? Main concerns are will the large plate style 1937 front engine mount work and will my 1937 transmission work with the engine. I have the 1937 parts from the flywheel back available. 

 Also is there reference material anywhere that explains the differences between the Dodge/Chrysler/Desoto flat sixes as far as interchange?

Edited May 13, 2020 by rustystuff

[greg g]

DeSoto and Chrysler in US used engines that are 25 inches long measured at the head, Dodge and Plymouth measured 23.5.  So the basic answer is yes. Not familiar with the front motor mount you are describing but it should exchange to the newer block.  The bell housings should also.  Are you planning on keeping the early flywheel?  There might be a difference in ring gear tooth count so keep the starter or Bendix gear that matches the flywheel.  The exhaust manifold may also be different as to the location of the outlet.  Some were to the rear of #6 cylinder, some were between # 4 and #5. Not a big concern except for the configuration of the front exhaust pump. The later engine may have some electrical connections for elec choke and to the carb for the semi auto trans. While it may not be an actual bolt for bolt swap, the differences are all fairly easy to address.

 

Where are you in NY?? we need more old Mopars out and about.

[rustystuff]

 Hi Greg, 

   I am near Poughkeepsie, about 90 minutes north of NYC. I have to see how the front engine mount is bolted on, I just want to make sure there are not special mounting bosses or something that may not be on a newer engine. I would think I could find a 50s running flat head without too much trouble, so that would be great if it would work.  I found a picture on the net that shows the front motor mount style I have, it is a large plate above the crank pulley and runs to the frame. 

 

 

[greg g]

If it bolts on to the block behind the water pump pulley it should work haven't seen one like that before.  Hopefully some of the guys more familiar with earlier stuff will chime in.

[Doug&Deb]

Measure the length of the original engine. The 51 engine is 25 inches long. If they match that makes it easier.

[RobertKB]

I put a ‘55 flathead in a ‘38 Chrysler I restored and have since sold. ‘38 Front  engine mount and bell housing bolted right on. Transmission worked well too.

 

I used the newer  flywheel and starter that matched it.  
 

Good luck.      
 

    

Edited May 13, 2020 by RobertKB

[falconvan]

Nice project! That’s an interesting front mount; really beefy looking.